Wireless communication systems are widely deployed to provide various types of communications such as voice and data for a number of associated users. These systems may be implemented based on various access techniques such as, for example, code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), or some other multiple access techniques to transmit and/or receive data traffic over communication channels such as, for example, Multiple-Input-Multiple-Output (MIMO) channels. MIMO-based wireless communication systems have received significant attention in the last years as a means to achieve a significantly increased capacity through spatial multiplexing. A MIMO communication system employs multiple transmit (NT) antennas and multiple receive (NR) antennas for communicating multiple spatially independent data streams. In an exemplary MIMO downlink communication system, the transmitter (e.g., a base station) is provided with multiple transmit antennas capable of transmitting multiple spatially independent data streams, while the receiver (e.g., a mobile device) is equipped with multiple receive antennas to receive one or more of the multiple spatially independent data streams transmitted by the base station. A MIMO channel is formed by multiple transmit (NT) antennas and multiple receive (NR) antennas. A connection from a multiple-antenna base station with multiple transmit (NT) antennas to a single multiple-antenna mobile device with multiple receive (NR) antennas is called a single user downlink MIMO channel. The single user downlink MIMO channel may be decomposed into NC independent channels, with NC≦min {NT, NR}. Each of the NC independent channels is referred to as a spatial subchannel of the single user downlink MIMO channel. A communication channel such as a single user downlink MIMO channel is characterized by fluctuating signal levels and additive interference from in-cell and outer-cells. Signals transmitted over the single user downlink MIMO channel exhibit Inter-Path Interference (IPI) and fading, which directly affect the communicated signals and result in time-varying signal quality such as varying signal to interference plus noise power ratio (SINR). Special means such as, for example, error-correcting codes, power control and/or transmit-receive diversity may be utilized so as to combat these effects and provide reliable communications.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.